In the coming decades, hydrogen may be stored and used in new energy systems in vast quantities. Advances in fuel cells and advances to electric vehicles have brought hydrogen gas to the forefront of the various energy candidates to meet our future energy demands. However, there remains a general perception about the safety with respect to the widespread use of hydrogen gas as a fuel.
Concerns about hydrogen safety could be a longstanding and formidable barrier to its early introduction as a fuel in clean, sustainable energy systems. Such safety concerns are particularly difficult to overcome where there is limited operating experience and few, if any, published codes and standards. This negative perception affects consumer acceptance, production liability, insurability, permitting requirements, and the establishment of other ordinances and regulations, all of which are required for the widespread introduction of commercial hydrogen gas fuels, products, or systems into the marketplace.
Prominent among these concerns may be the possibility of a fire or explosion resulting from an undetected hydrogen gas leak. Current technology for detecting the presence of free hydrogen in a mixture of other gases has improved, and there exist various regulations requiring the use of hydrogen detection devices to detect the presence of hydrogen gas at 1 volume percent where gaseous hydrogen buildup is possible (29 C.F.R. 1910.106 (1996), hereby incorporated by reference) and at 0.4 volume percent for confined spaces (29 C.F.R. 191.146 (1996), hereby incorporated by reference). Simple, cost effective means for hydrogen gas detection and indication of information to persons about the level of hydrogen gas present in various environments in which hydrogen gas can be used or may accumulate has been given little, if any, attention and significant problems remain, yet to be resolved.
A significant problem with existing hydrogen gas sensor technology can be that it may be too large, too immobile, too complex, or too expensive to introduce into a mass market as a personal hydrogen gas detection or indicator technology. Mass spectrometers and chromatographs, for example, are extremely sensitive, but are also large, immobile, expensive, require skilled operators, and may have long response times.
Another significant problem with existing hydrogen gas sensor technology can be that it is not practical for continuous monitoring. Leak detection by observing the formation of bubbles in a liquid material, for example, can be one of the simplest manners of leak detection but only has practical use in the detection of inert gases that are at low pressure and when the temperatures is above freezing.
Another significant problem with existing hydrogen gas sensor technology can be that the hydrogen sensor can be dangerous to use. For example, glow plug technology ignites combustible gas and the heat of combustion is then measured. As can be understood, an ignition source can be dangerous when there is a large amount of the combustible material available.
Another significant problem with existing hydrogen gas sensor technology can be that the technology lacks specificity to hydrogen gas. For example, catalytic combustion sensors can detect hydrogen gas by sensing the heat generated by the combustion of hydrogen with oxygen on the surface of a catalyst such as palladium or platinum. However, catalytic sensors also combust other gases such as methane as well and may provide false indications of the presence of hydrogen gas. Ultrasonic leak detectors are not specific to hydrogen gas and cannot differentiate combustible mixtures from non-combustible mixtures of gases.
Another significant problem with existing hydrogen gas sensor technology can be that the technology does not work in certain environments. Catalytic combustion sensors may not work in atmospheres of inert gas or pure hydrogen and semiconducting oxides may not work in atmospheres of inert gas. Bubble detection, electrochemical sensors using selectably permeable membranes, or thermal conductivity sensors may not work or may work inconsistently at lower or variable temperatures.
Another significant problem with existing hydrogen gas sensor technology can be that the technology may not provide discrete indicia beyond the change in the physical or electrical properties of the hydrogen gas sensor itself that can be visually, audibly or tactily discerned or observed by persons in the environment surrounding the hydrogen gas sensor.
The instant invention addresses each of the above-mentioned problems in a practical manner.